Comminuting apparatus

ABSTRACT

A two stage comminuting apparatus is provided for preparing waste solids for disposal. The apparatus contemplates a wet pulping of solids for the purpose of reducing the solids to a predetermined size, such pulping being effected by an abrading type nonjamming pulper. The pulped solids then may be fed to a positive grinder, after passing through a sump or other type of trap for selecting nongrindables therefrom. The positive grinder further reduces in size those particles which have been metered to size in the pulping stage.

United States Patent [56] References Cited UNITED STATES PATENTS 2,072,710 3/1937 Crane.... 241/185UX 2,672,075 3/1954 Fraser. 241/43 2,674,927 4/1954 Wicksell. 241/46. 17X 3,005,597 10/1961 Neidl 241/185UX 3,164,329 1/1965 Wandel..... 241/46.17X 3,450,354 6/1969 Helfgott et a1. 241/43 Primary Examiner-Frank T. Yost Att0rneyPaul and Paul llllllll lllllll CGMMHNUTHNG APPARATUS BACKGROUND OF THE INVENTION In todays industrialized society, waste disposal has become a major problem, it having been recognized that conventional door-to-door trash collection techniques cannot continue to provide the type of efficient service required, particularly in urban areas.

Techniques have therefore been investigated with regard to domestic and commercial removal of waste solids through sewage pipelines and the like. Some proposals have been directed toward providing comminuting stations throughout sewage lines, in a given community, and others have been directed toward providing individual comminuting stations for hotels, office buildings, manufacturing plants and thelike. In either case, the problem remains that random aggregate mixtures of trash comprising paper, plastics, metal articles such as cans, glass articles and the like must first be reduced in size to a degree small enough to effectively and efficiently be further handled, either through pipelines, or through other means for carrying such rubble from its locus of generation.

Prior art types of comminuting apparatus have principally been directed toward crushing and grinding waste solids into particles sufficiently small that they occupy a sufficiently diminished volume to be carried away from their situs of generation. However, such prior art techniques have essentially relied upon positive grinding apparatus which is not capable or effective for handling a wide variety of substances of various densities, sizes, materials and the like, such as cans, glass, plastics, papers, wood and the like. The prior art apparatus have therefore required the use of a plurality of selection stations, whereby rubble of different types may be separated into various categories, with each such category being handled for comminuting purposes by a separate positive type of grinder specifically adapted for rubble in that category. Thus, a heavy-duty grinder would be required for pulverizing metallic components of trash, a light-duty grinder for pulverizing paper components, etc.

Pulping apparatus, such as that disclosed in our copending US. Pat. application Ser. No. 580,445 filed Sept. 20, 1966 now US. Pat. No. 3,489,356 has been developed, which operates on trash mixtures in a highly satisfactory manner, for pulping the waste while submerged in water, to a predetermined size depending upon the exit ports from the pulping tank. Such a unit abrades the waste while the waste is submerged in water, and is generally referred to as being of nonjamming type. Such units are generally large and can therefore handle large quantities of waste. Also, because such units are nonjamming, they have capabilities for effectively handling many types of waste including nuts, bolts, glass, cans, rags, paper, food waste, and various metal articles and the like. Many of the above-enumerated items would stall or jam a positive grinder which may perhaps not have the required power for crushing such items. In a pulping type grinder, waste is abraded into the desired size. However, because of the nonjamming nature of such a pulping apparatus, it tends to have a low capacity when handling certain types of materials. For example, light gage plastic a few thousands of an inch thick may be readily torn into pieces of irregular shape and of several square inches in area. However, further reduction in size of such pieces requires a great amount of work, often an impracticability. While it is possible to enlarge the size of exit openings from the pulper, this would then require the pipeline carrying debris away from the pulper to be considerably larger than a practicable size, in order to prevent clogging. Furthermore, pulpers generally have great difficulty in reducing the size of other tough, resilient materials, and other material as well. Heavy gage plastics, such as plastic tubing may be propelled back and forth in the pulping tank and finally discharged through the pulper exit openings, in that the diameter, for example, of tubing may be of sufficient size to permit passage through such exitopenings, but its length may SUMMARY OF THE INVENTION The present invention is directed toward overcoming the disadvantages of prior art types of waste comminuting ap paratus, and toward solving the problems heretofore attended to pulping type waste abrasion devices, and providing a composite apparatus or system which utilizes the advantageous characteristics of both types of comminuting devices, but which utilizes the pulping apparatus not, as a means for reducing solid waste to its final size, but as a means for metering the size of waste particles such that aggregate waste materials may be delivered to a positive grinding station, free of classification and selection techniques whereby the waste would be classified into a plurality of categories, as has been required by prior art devices.

Accordingly, it is a primary object of this invention to pro vide an apparatus for facilitating the preparation and eventual disposal of waste solids, wherein atwo-stage grinding system is provided, one being a pulping type grinder, and the other being a positive type grinder.

It is a further object of this invention to accomplish the above object wherein the positive grinder is disposed downstream of the pulping grinder, with the pulping grinder reducing waste to a size which the positive grinder is capable of handling, with the pulping grinder thus metering the size of solids delivered to the positive grinder.

It is yet another object of this invention to accomplish the above objects, wherein a trap is disposed between the pulping and the positive grinders, for accumulating selected particles, such as particles of very high density, not readily handled by the positive grinder.

It is a further object of this invention to provide a pulping and grinding apparatus which is adapted for connection to or within a pipeline or other type of zone, wherein the pulping portion of the apparatus is adapted for metering or reducing the size of particles entering the zone, followed by a positive grinding apparatus for further reducing the size of particles delivered thereto.

Other objects and advantages of the present invention will be readily apparent to one skilled in the art upon studying the following detailed description of the preferred embodiment and operation thereof, as well as the appendant claims.

IN THE DRAWING The drawing FIGURE is a side elevational view, with portions broken away and illustrated in section for purposes of clarity, of a two-stage grinding apparatus of this invention wherein the different types of apparatus for effecting the grinding or comminuting operations are clearly illustrated.

Referring now to the drawing in detail, it is seen that there is provided a system 5, comprising a pulping tank apparatus 6, a sump-type trap 7, a positive grinding apparatus 8, a water press 10, a water return line 11 to the tank 6, and drive means 12 and '13 for the pulping and positive grinding operations, respectively.

The pulping tank apparatus 6, comprises a tank constructed generally along the lines of that disclosed in copending application Ser. No. 580,445, filed Sept. 20, 1966, having a lower tank portion 14, a removable upper tank or cover portion 15, and a slidable or otherwise openable solids-receiving door 16. A water inlet line 17 may be provided, in that the pulping apparatus 6 generally operates with the waste solids submerged during the size-reducing abrasive action. In the alternative, or in addition, return water may be provided from the water press through the return line 11, for supplying the water to the pulping tank apparatus 6.

The tank apparatus 6 includes a sunken centrally disposed lower wall 18, vertically spaced from a circular outermost wall portion by a screen or perforated member 21, having a plurality of outlet holes 22 therein, which are sized to facilitate the passage therethrough of solid waste particles which have been reduced to a desirable selected size.

A rotatable abrading plate 23 is provided, carried by a shaft 24 extending upwardly through the bottom wall 18, centrally thereof, with the plate 23 being generally circular in construction and having solidscutting elements 25 on an upper surface thereof, in addition to combination cutting and impelling elements 26 disposed thereon; the elements 26, in addition to being adapted for facilitating the size reduction of solid particles within the lower tank portion 14, such elements 26 being also adapted and angularly disposed for impelling solids of the selected size through the outlet ports or holes 22, into a collecting chamber 27 disposed beneath the lower wall 18.

The collecting chamber 27 comprises an outlet duct 28 from the pulping tank apparatus 6, for delivery of pulped solids to the positive grinder 8, either directly or through the sump-type trap 7.

The shaft 24 may thus extend through a lower wall of the duct 28, and therefore a gasket 30 or other type of sealing means may be required for the shaft 24. A pulley 31 may be fixedly connected to the shaft 24, being rotated by a driving belt 32.

The sump trap 7 may comprise a generally upstanding duct or pipelike member, having a lower portion 33 with a closed bottom wall 34, and an upper portion 35 with an open top wall 36 for providing an air vent at the upper end. A baffle 37 may be provided, disposed across, but spaced from the inlet 38 of the sump 7, to assure that excessively dense items, such as heavy bolts and the like, which are small enough to pass through the openings 22 in the screen plate 21 of the pulping apparatus 6, do not enter the positive grinding apparatus 8, and damage chopping teeth and the like thereof, and to further assure that such excessively dense debris will not be carried toward the positive grinder 8, in the normal course of flow. The dense debris would thus strike the baffle plate 37 and drop into the bottom portion 33, of the trap 7, to be removed in a hand removal operation, or the like.

An outlet line 40 from the trap 7 is provided, which also comprises the inlet to the positive grinder 8.

The grinder 8 comprises a housing 41 for a shaft 42, the shaft 42 having a pulley 43 at one end thereof, which is rotatably driven by a drive belt 44.

At the leftmost end of the shaft 42, as viewed in the drawing, there is provided an angularly disposed plate 45, with serrations 46 on its periphery 47, such serration 46 being adapted to mesh with teeth or the like 48, disposed on an interior surface 50 of the housing 41, adjacent to the path of travel of the periphery 47 of the plate 45, during its rotation with the shaft 42. This type of grinder 8 which includes meshing opposing members such as teeth 46 and 48 or the like which are designed to grind material therebetween is herein termed a positive" grinder in distinction to a pulper 6 which functions by continued abrasion as discussed above.

The particular orientation of the plate 45, and its position relative to the outlet 50 of the positive grinder 8 are such that the positive grinder is of the pumping type, with the plate being adapted to pump positively ground particles upwardly through the outlet opening of the grinder 8, through the pipeline 51, to the water press 10.

The water press 10 is of the general type disclosed in U.S. Pat. application Ser. No. 580,711, filed Sept. 20, 1966, and comprises a liquid and pulp or other ground particle inlet 51, a housing 52, a pressed pulp and debris outlet 53, and outlet 54 for water which has been pressed from the pulp within the press 10. The water 54 may pass into the return line 11, to the pulping apparatus 6, rather than discharge such water to sewage or the like, if desired.

OPERATION It is thus seen that accumulated trash, and other waste solids and the like may be collected and enter into the pulping tank apparatus 6 through the slidable openings 16, wherein they become immersed within the water fluid within the tank bottom portion 14. The rotating plate 23and its cutting elements 25 and 26 thereby abrade against the solid particles, glass, cans, plastic and the like, and continue to do so until such particles are of a sufficient size to pass through the openings 22 in the screen plate 21. The passage of such selectively sized particles through the opening 22 is facilitated by an impelling ef-' fect from the rotating elements 26.

In the pulping tank 6, most of the debris will be reduced to a desirable size. However, some of the debris, may comprise elongated tubular plastic members and the like which are of sufficient size to pass through the holes 22, and to be conveyed to the positive grinder 8, but which are of too great a size to enter the water press 10, or to be carried away by a sewage pipeline. It is on particles such as these, as well as rags, plastic sheets and the like that the positive grinder 48 is particularly advantageous, in that such particles may readily be reduced to size, and there would be no tendency for such particles to bounce" around inside the housing 41, as there may be for resilient plastic particles within the tank lower portion 14 of the pulping apparatus 6.

The positive grinding apparatus 8 is also used for further reducing the size of all other particles which pass through the outlet openings 22 of the pulping apparatus 6. Accordingly, the selection of size of the holes 22 depends upon the capacity and horsepower drive requirements of the positive grinder 8. The size of the holes 22 must thus be dependent upon the balance of work between the pulping apparatus 6 and the positive grinder 8. For example, the capacity of the primary or pulper grinder 6 is a function of the amount of work which the abrading plate 23 will do. If the discharge openings 22 in the sizing ring or screen 21 are one-half inch in diameter, then each discharge opening 23 will be only one quarter the area that would be bad if the holes 23 were each 1 inch in diameter. Therefore, four times as much work must be done to grind or pulp the particles to pass through a 16inch diameter hole, than to pass through a 1-inch diameter hole. By carefully selecting the sizing ring 21 to have desirably sized holes 22, the amount of work which will be done within the pulping apparatus 6 can be limited to an optimum amount of such work only, with the positive grinder 8 performing the additional work. The time requirements for the entire grinding operation are thus reduced, in that a larger outlet duct 28 may be used, It is thus seen that this system contemplates a maximum efficient use of horsepower requirements for each of the grinding apparatuses 6 and 8.

The advantages of such a system as the one described above should now be readily apparent to one of ordinary skill in the art. Such a system can readily be incorporated into the construction of an office building, hotel, manufacturing plant or the like. It is also contemplated that an abrading-type pulping unit, such as one having an abrading plate like that of 23, along with a serially connected positive grinder 8 may be installed in sewage pipelines and the like for achieving a similar two-stage grinding effect, for example on a macroscopic scale in conjunction with the pipeline collection of solid waste for an entire community. If such were desired, two-stage grinding of the type set forth herein could be installed in various pipeline zones throughout a waste pipeline network, for example for a city or the like.

From the foregoing comments it will be readily apparent to one of ordinary skill in the art that various modifications may be made in the system, its apparatus, structural details and means of connection, as well as in the use thereof, all within the spirit and scope of the invention, as defined in the appended claims.

We claim: I I

l. A communiting apparatus for preparation of waste solids for disposal comprising means for continuously pulping solids by abrasion in a fluid medium .to a predetermined reduced particle size and means for grinding particles of reduced size; said grinding means being connected in series to said pulping means, downstream thereof, including a trap means disposed in series connection between said, pulping means and said grinding means for accumulatingselected particles not readily grindable by said grinding means.

2. The apparatus defined in claim 4, wherein said pulping means is of the liquid-receiving type having movable abrading plate means mounted adjacent outlet openings of selected size; said opening size being determined by the desired predetermined size of particles to be discharged therethrough.

3. The apparatus defined in claim 4, wherein said pulping means comprises a tank having an upper inlet and a plurality of lower outlet openings, with a rotatable abrading plate disposed adjacent said openings for reducing the size of solid particles to be impelled through said openings.

4. The apparatus defined in claim 1, wherein said trap means is of the sump type.

5. The apparatus defined in claim 1, wherein said positive grinding means is of the particle-chopping type.

6. The apparatus definedin claim 5, wherein said positive grinding means includes meshing teeth.

7. The apparatus defined in claim 1, wherein said positive grinding means is of the pumping type. 1

8. The apparatus defined in claim 1, wherein said pulping means and said grinding means are operative in a water medium, including a dewatering unit serially connected to said positive grinding means downstream thereof.

9. The apparatus defined in claim 8, including return line means between said dewatering unit and said pulping means for returning water extracted from pulped and ground solids in said dewatering unit.

10. The apparatus defined in claim 2 and said plate means being rotatable for reducing the size of solid particles to be impelled through said openings and including a trap means disposed in series connection between said pulping means and said grinding means for accumulating-selected particles not readily grindable by said grinding means and wherein said trap, means is of the sump type, wherein said positive grinding means is of the pumping type having intermeshing particle chopping teeth.

11. The apparatus defined in claim I, wherein said pulping means includes an abrading plate means comprising a rotatable plate which includes means for impelling particles of reduced size in the zone through an outlet of said pulping means. 

1. A communiting apparatus for preparation of waste solids for disposal comprising means for continuously pulping solids by abrasion in a fluid medium to a predetermined reduced particle size and means for grinding particles of reduced size; said grinding means being connected in series to said pulping means, downstream thereof, including a trap means disposed in series connection between said pulping means and said grinding means for accumulating selected particles not readily grindable by said grinding means.
 2. The apparatus defined in claim 4, wherein said pulping means is of the liquid-receiving type having movable abrading plate means mounted adjacent outlet openings of selected size; said opening size being determined by the desired predetermined size of particles to be discharged therethrough.
 3. The apparatus defined in claim 4, wherein said pulping means comprises a tank having an upper inlet and a plurality of lower outlet openings, with a rotatable abrading plate disposed adjacent said openings for reducing the size of solid particles to be impelled through said openings.
 4. The apparatus defined in claim 1, wherein said trap means is of the sump type.
 5. The apparatus defined in claim 1, wherein said positive grinding means is of the particle-chopping type.
 6. The apparatus defined in claim 5, wherein said positive grinding means includes meshing teeth.
 7. The apparatus defined in claim 1, wherein said positive grinding means is of the pumping type.
 8. The apparatus defined in claim 1, wherein said pulping means and said grinding means are operative in a water medium, including a dewatering unit serially connected to said positive grinding means downstream thereof.
 9. The apparatus defined in claim 8, including return line means between said dewatering unit and said pulping means for returning water extracted from pulped and ground solids in said dewatering unit.
 10. The apparatus defined in claim 2 and said plate means being rotatable for reducing the size of solid particles to be impelled through said openings and including a trap means disposed in series connection between said pulping means and said grinding means for accumulating selected paRticles not readily grindable by said grinding means and wherein said trap means is of the sump type, wherein said positive grinding means is of the pumping type having intermeshing particle-chopping teeth.
 11. The apparatus defined in claim 1, wherein said pulping means includes an abrading plate means comprising a rotatable plate which includes means for impelling particles of reduced size in the zone through an outlet of said pulping means. 